Protected HepG2 Cells Research Articles

Pachypodol, a Methoxyflavonoid Isolated from Pogostemon cablin Bentham Exerts Antioxidant and Cytoprotective Effects in HepG2 Cells: Possible Role of ERK-Dependent Nrf2 Activation.

Oxidative stress has been implicated in the pathogenesis of many diseases including chronic liver diseases. Nrf2 is a master transcriptional factor regulating the induction of cellular antioxidant defense systems. Here, the Nrf2-activating effect of the crude methanol extract of dried leaves of Pogostemon cablin Bentham was demonstrated by measuring the antioxidant response element (ARE)-driven luciferase activity and pachypodol, 4′,5-dihydroxy-3,3′,7-trimethoxyflavone, was isolated by bioactivity-guided fractionation and further separation using chromatographic techniques. To our knowledge, this is the first study to evaluate the antioxidant and cytoprotective effects of pachypodol in HepG2 cells as well as the underlying molecular mechanisms. Indeed, pachypodol protected HepG2 cells from cell death caused by tert-butylhydroperoxide-induced oxidative stress and also attenuated ROS production. The ability of pachypodol to activate Nrf2/ARE pathway was further confirmed by observing Nrf2 expression in nuclear fraction, mRNA levels of Nrf2 target antioxidants, and cellular glutathione content in HepG2 cells. Extracellular signal-regulated kinase (ERK) is one of the important kinases involved in Nrf2 activation. Pachypodol increased ERK phosphorylation and ERK inhibition by PD98059 totally abrogated the increase in ARE luciferase activity, nuclear Nrf2 accumulation and mRNA levels of antioxidant enzymes by pachypodol. In conclusion, pachypodol isolated from P. cablin can protect hepatocytes from oxidative injury, possibly mediated by enhancing endogenous antioxidant defense system through ERK-dependent Nrf2 activation.

Effect and mechanism of liraglutide on the apoptosis of human hepatocellular carcinoma HepG2 cells induced with palmitic acid

Objective: To observe whether liraglutide protects HepG2 cells from lipotoxicity by affecting mitogen-activated protein kinase (MAPKs) pathway. Methods: HepG2 cells were induced with 400μmol/L palmitic acid, and cells were treated with a final concentration of 100 nmol/L liraglutide. In addition, JNK inhibitor (SP600125) and p38 MAPK inhibitor (SB203580) were added in advance, respectively. Apoptosis rate, malondialdehyde (MDA) content, and caspase3 activity were detected. Western blot was used to detect p38 mitogen-activated protein kinase (p38 MAPK), c-jun amino terminal kinase (JNK), cytochrome oxidase P450 2E1 (CYP2E1), glucose regulatory protein 78 (GRP78), activated caspase 3, B cell lymphoma associated Protein X (Bax), B cell lymphoma 2 (Bcl-2), and expression of C/EBP homologous protein (CHOP) protein. LSD or Dunnett's T3 test were used to compare the mean of multiple samples. Results: Palmitic acid increased the phosphorylation of p38 MAPK and JNK in HepG2 cells (P< 0.05). Furthermore, it increased the expression of GRP78, CHOP, CYP2E1, MDA, Bax, caspase3 and apoptosis rate, but inhibited the expression of Bcl-2 (Pvalue < 0.05). SP600125 and SB203580 had inhibited oxidative stress and apoptosis induced by palmitic acid (including CYP2E1, MDA, Bax, Bcl-2, caspase3, CHOP) (P< 0.05). The phosphorylation level of p38 MAPK and JNK was reduced with liraglutide and the expression of apoptosis-related proteins (Bax, Bcl-2, caspase3, CHOP) (P< 0.05) was regulated. There was no significant difference in the effect of liraglutide on apoptotic proteins (Bax, Bcl-2, caspase-3, CHOP) (P> 0.05) after pretreatment with those two inhibitors. Conclusion: Palmitic acid has strong lipotoxicity to HepG2 cells and induces apoptosis. Glucagon-like peptide-1 analogue, liraglutide may improve lipotoxicity of palmitic acid by mediating p38 MAPK and JNK pathways.

Isoflavone biochanin A, a novel nuclear factor erythroid 2-related factor 2 (Nrf2)-antioxidant response element activator, protects against oxidative damage in HepG2 cells.

Isoflavones are one group of the major flavonoids and possess multiple biological activities due to their antioxidant properties. However, a clear antioxidant mechanism of dietary isoflavones is still remained to be answered. In this study, the effects of isoflavones on the nuclear factor E2-related factor 2 (Nrf2)-antioxidant response element (ARE) signaling pathway and the underlying molecular mechanisms were investigated. Results showed that isoflavones are potential Nrf2-ARE activators while their activities were structure dependent. Biochanin A (BCA), an O-methylated isoflavone with low direct antioxidant activity, can effectively protect HepG2 cells against tert-butyl hydroperoxide (t-BHP)-induced oxidative damage via activation of the Nrf2 signaling, and thereby the induction of downstream cytoprotective enzymes including NAD(P)H quinone oxidoreductase-1, heme oxygenasae-1, and glutamate-cysteine ligase catalytic subunit. A molecular docking study revealed that BCA could directly bind into the pocket of Kelch-like erythroid cell-derived protein with CNC homology (ECH)-associated protein 1 (Keap1), a cytoplasmic suppressor of Nrf2, to facilitate Nrf2 activation. The upstream mitogen-activated protein kinase (MAPK) pathways were also involved in the activation of Nrf2 signaling. These findings indicate that the protective actions of dietary isoflavones against oxidative damage may be at least partly due to their ability to enhance the intracellular antioxidant response system by modulating the Nrf2-ARE signaling pathway.

Oleic acid ameliorates palmitic acid induced pyroptosis by attenuating endoplasmic reticulum stress in HepG2 cells

BackgroundIn the liver, chronic exposure to high FFAs in the context of hyperlipidemia or ectopic deposition of fat will result in nonalcoholic fatty liver disease (NAFLD) ultimately. In the present study, the mechanisms of saturated fatty acids induced cell death have been investigated. Particular attentions have been pay on caspase‐1 mediated pyroptosis and endoplasmic reticulum stress (ERS). In addition, the protective effects of a monounsaturated fatty acid, oleic acid (OA) against hepatic lipotoxicity was explored.MethodsHuman hepatoma cell line HepG2 was challenged by palmitic acid (PA) to induce lipotoxicity, and OA was supplemented concomitantly with PA to investigate its protective effects. Cell viability was determined by CCK8 assay and apoptosis was measured by flow cytometry. The expression of ER stress and pyroptosis related proteins was measured by Western blot or real‐time PCR. The morphology of pyroptosis was presented by PI staining and AO/EB Dyeingy. The expression level of gasdermin D (GSDMD), an executor of pyroptosis, was determined by Western blot and immunofluorescence assay.Results1) PA deteriorated cell viability of HepG2 cells in dose and time dependent manner. PA of 0.4 mM has remarkably decreased the cell viability (60%) compared to controls after 24 h incubation. Stimulation with OA of 0.2 mM was nontoxic to cell viability, but the combination of OA and PA robustly restored the cell viability to normal level. 2) Inconsistent with the results in cell viability, PA challenge for 24 h has not significantly increased cell apoptosis in HepG2. However, the expression of inflammasome and pyroptosis markers, including caspase‐1/p20, IL‐1 beta, IL‐18, NLRP3 and GSDMD was significantly up‐regulated, indicating that pyroptosis was activated obviously. In addition, the occurrence of pyroptosis was convinced by the increased AO/EB double positive cells as well as increased GSDMD expression after PA stimulation, suggesting a kind of gasdermin‐mediated programmed necrosis, which is a typical feature of pyroptosis. Interestingly, OA substantially suppressed the PA induced activation of pyroptosis, evidenced by significantly down‐regulated expression of above markers. 3) Meanwhile, the expression of ER stress related markers was found notably up‐regulated after 24 h PA exposure, including CHOP, phosphorylated PERK, and GRP78 on protein levels, and UPR genes, such as XBP1, CHOP, and GRP78 on mRNA levels. In consistence, OA attenuated PA triggered ER stress in HepG2 cells.ConclusionCompared to apoptosis, caspase‐1 mediated pyroptosis might be an essential form of cell death driven by excessive uptake of saturated fatty acid. Monounsaturated oleic acid was able to robustly protect HepG2 cells against lipotoxicity. The down‐regulation of GSDMD expression and consequently amelioration of pyroptosis may involve in the mechanisms of OA mediated protective action, and the OA mediated alleviation of PA triggered ER stress might be a possible upstream mechanism of its effects on pyroptosis.Support or Funding InformationThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Protective effect of inducible aldo-keto reductases on 4-hydroxynonenal- induced hepatotoxicity

4-Hydroxynonenal (HNE), an end-product of lipid peroxidation generated in response to oxidative stress, has been implicated in the pathophysiology of chronic liver diseases. HNE is very reactive that forms Michael adducts with nucleophilic sites in DNA, lipids and proteins. At high concentrations, HNE causes rapid cell death associated with depletion of sulfhydryl groups and inhibition of key metabolic enzymes. At low concentrations, HNE stimulates expression of genes that are part of an adaptive response. In this study, we show that sub-lethal concentrations of HNE induce mRNA expression levels of heme oxygenase-1 (HO-1) (2.5-fold), NADPH:quinone oxidoreductase (NQO1) (4.5-fold), AKR1C3 (2-fold) and AKR7A2 (3-fold) enzymes. Protein expression levels of AKR1C and AKR7A2 are induced by 2- and 1.5-fold following exposure to HNE. The role of AKR1C3 and AKR7A2 in protecting HepG2 cells against HNE toxicity was investigated through using RNAi. Results show that AKR7A2, but not AKR1C3 contributes to the protection against HNE toxicity in HepG2 cells. Moreover, transcriptional factor nuclear factor erythroid 2 p45-related factor 2 (Nrf2) is activated by HNE through translocation to the nucleus. Overexpressing AKR7A2 could rescue the effect of knocking down Nrf2 on HNE-induced cytotoxicity. Furthermore, a natural compound 7-hydroxycoumain, an AKR7A2 inducer, shows hepatoprotection against HNE via AKR7A2 induction. Hence, the inducible AKR7A2 has provided a new therapeutic target to treat chronic liver disease.

Preventive Effect of YGDEY from Tilapia Fish Skin Gelatin Hydrolysates against Alcohol-Induced Damage in HepG2 Cells through ROS-Mediated Signaling Pathways.

According to a previous study, YGDEY from tilapia fish skin gelatin hydrolysates has strong free radical scavenging activity. In the present study, the protective effect of YGDEY against oxidative stress induced by ethanol in HepG2 cells was investigated. First, cells were incubated with YGDEY (10, 20, 50, and 100 μM) to assess cytotoxicity, and there was no significant change in cell viability. Next, it was established that YGDEY decreased the production of reactive oxygen species (ROS). Western blot results indicated that YGDEY increased the levels of superoxide dismutase (SOD) and glutathione (GSH) and decreased the expression of gamma-glutamyltransferase (GGT) in HepG2 cells. It was then revealed that YGDEY markedly reduced the expressions of bax and cleaved-caspase-3 (c-caspase-3); inhibited phosphorylation of Akt, IκB-α, p65, and p38; and increased the level of bcl-2. Moreover, the comet assay showed that YGDEY effectively decreased the amount of ethanol-induced DNA damage. Thus, YGDEY protected HepG2 cells from alcohol-induced injury by inhibiting oxidative stress, and this may be associated with the Akt/nuclear factor-κB (NF-κB)/mitogen-activated protein kinase (MAPK) signal transduction pathways. These results demonstrate that YGDEY from tilapia fish skin gelatin hydrolysates protects HepG2 cells from oxidative stress, making it a potential functional food ingredient.

SVIP alleviates CCl4-induced liver fibrosis via activating autophagy and protecting hepatocytes

Prolonged parenchymal cell death leads to activation of fibrogenic cells and extracellular matrix accumulation and eventually liver fibrosis. Autophagy, a major catabolic process of intracellular degradation and recycling, participates in hepatic fibrosis. However, the precise role of autophagy in the pathogenesis of hepatic fibrosis is controversial. The present study aims to investigate the key role of small VCP/p97 interacting protein (SVIP) against CCl4-induced hepatic fibrosis via activating autophagy. Autophagy could be activated by SVIP in HepG2 cells, but starvation cannot increase SVIP expression in vitro and in vivo. Moreover, SVIP expression, in agreement with autophagic activity and the volume of lipid droplets, first increases and then decreases during the progression of liver fibrosis with CCl4 treatment in vivo and in vivo. Further, overexpression of SVIP can protect HepG2 cells from the toxicity of CCl4, which could be enhanced by starvation. Finally, starvation keeps SVIP and autophagy at such high levels in the rat livers that markedly delays the progress of hepatic fibrosis. Probably, the protective effect of SVIP is associated with stabilizing nuclear factor (erythroid-derived 2)-related factor 2 (Nrf2) and transcription factor EB (TFEB). The current study provides insight into the biological role of SVIP and autophagy in regulating hepatic fibrosis, targeting SVIP might be a novel therapeutic strategy in the future.

Role of the Death Receptor and Endoplasmic Reticulum Stress Signaling Pathways in Polyphyllin I-Regulated Apoptosis of Human Hepatocellular Carcinoma HepG2 Cells.

Polyphyllin has been reported to exhibit anticancer effects against various types of cancer via the proapoptotic signaling pathway. The aim of the present study was to investigate the role of the endoplasmic reticulum stress and death receptor signaling pathways in PPI-induced apoptosis of human hepatocellular carcinoma HepG2 cells. Analysis demonstrated that PPI could significantly inhibit the proliferation and induce apoptosis of HepG2 cells in a dose- and time-dependent manner. Investigation into the molecular mechanism of PPI indicated that PPI notably mediated ER stress activation via IRE-1 overexpression and activation of the caspase-12 to protect HepG2 cells against apoptosis. In addition, PPI markedly induced the expression of death receptors signaling pathways-associated factors, including tumor necrosis factor (TNF) receptor 1/TNF-α and FAS/FASL. Additionally, suppression of the death receptor signaling pathways with a caspase-8 inhibitor, Z-IETD-FMK, revealed an increase in the death rate and apoptotic rate of HepG2 cells. Collectively, the findings of the present study suggested that the ER stress and death receptor signaling pathways were associated with PPI-induced HepG2 cell apoptosis; however, endoplasmic reticulum stress may serve a protective role in this process. The combination of PPI and Z-IETD-FMK may activate necroptosis, which enhances apoptosis. Therefore, the results of the present study may improve understanding regarding the roles of signaling pathways in PPI regulated apoptosis and contribute to the development of novel therapies for the treatment of HCC.

Nano-encapsulation using macrocyclic carbohydrate polymers (β-cyclodextrins) of Periploca angustifolia extract: Physical stability and protective effect against cadmium-induced alterations in HepG2 cells

The nano-encapsulation of Periploca angustifolia phenolic extract using the macrocyclic carbohydrate polymers (β‑cyclodextrins) is a most approach compared with other encapsulation methods. In this work, the β‑Cyclodextrins-PAE complex stability has been evaluated by advanced analytical methods and techniques including HPLC, FTIR and XRD. The results showed that CdCl2 treatment caused a significant decrease in cell viability. The CdCl2-induced damage in the HepG2 cells were significantly ameliorated (p < 0.001) by treatment of the PAE and β‑Cyclodextrins-PAE complex. Thus, pretreatment with 100 μg mL−1 of β‑Cyclodextrins-PAE complex significantly protect HepG2 cells against cytotoxicity induced by cadmium exposure more effectively than PAE only. However, Cd-intoxication significantly (p < 0.001) increased these enzymes activity. Additionally, reactive oxygen species generation was significantly decreased when cells were treated with nano-encapsulation PAE. The levels of supernatant antioxidant parameters including superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and GSH were significantly (p < 0.001) decreased in Cd-treated cells with concomitant enhancement of lipid peroxidation. In addition, β‑Cyclodextrins-PAE pretreatment significantly (p < 0.01) inhibited Cd-exposure activated the apoptotic pathway caspace-3 and caspace-9. This effect may be due to the ability of β‑Cyclodextrins molecules to enhance stability and permeability properties.

S-Allyl Cysteine Alleviates Hydrogen Peroxide Induced Oxidative Injury and Apoptosis through Upregulation of Akt/Nrf-2/HO-1 Signaling Pathway in HepG2 Cells.

Hydrogen peroxide (H2O2) mediated oxidative stress leading to hepatocyte apoptosis plays a pivotal role in the pathophysiology of several chronic liver diseases. This study demonstrates that S-allyl cysteine (SAC) renders cytoprotective effects on H2O2 induced oxidative damage and apoptosis in HepG2 cells. Cell viability assay showed that SAC protected HepG2 cells from H2O2 induced cytotoxicity. Further, SAC treatment dose dependently inhibited H2O2 induced apoptosis via decreasing the Bax/Bcl-2 ratio, restoring mitochondrial membrane potential (∆Ψm), inhibiting mitochondrial cytochrome c release, and inhibiting proteolytic cleavage of caspase-3. SAC protected cells from H2O2 induced oxidative damage by inhibiting reactive oxygen species accumulation and lipid peroxidation. The mechanism underlying the antiapoptotic and antioxidative role of SAC is the induction of the heme oxygenase-1 (HO-1) gene in an NF-E2-related factor-2 (Nrf-2) and Akt dependent manner. Specifically SAC was found to induce the phosphorylation of Akt and enhance the nuclear localization of Nrf-2 in cells. Our results were further confirmed by specific HO-1 gene knockdown studies which clearly demonstrated that HO-1 induction indeed played a key role in SAC mediated inhibition of apoptosis and ROS production in HepG2 cells, thus suggesting a hepatoprotective role of SAC in combating oxidative stress mediated liver diseases.

Purification and identification of two novel antioxidant peptides from perilla (Perilla frutescens L. Britton) seed protein hydrolysates.

Proteins were extracted from perilla (Perilla frutescens L. Britton) seed by-products and hydrolyzed with an alkaline protease. Antioxidant peptides were purified from the hydrolysate by size-exclusion chromatography and RP-HPLC. Two peptides with strong antioxidant activity were identified as Tyr-Leu (YL) and Phe-Tyr (FY) with the molecular mass of 294.33 Da and 328.33 Da, respectively. Synthesized YL and FY efficiently quenched free radicals (DPPH, ABTS and hydroxyl radicals) and showed high oxygen radical absorbance capacity. The two peptides also inhibited lipid peroxidation in the rat liver. Furthermore, YL and FY could protect HepG-2 cells against hydrogen peroxide-induced oxidative damage without cytotoxicity. Based on the structure-activity analysis, the Tyr residue was crucial for the antioxidant activity of YL and FY. The results indicate that the protein hydrolysate from perilla seed by-products possessed potent biological activity and can be utilized to develop health-related nutraceutical ingredients.

Acetophenone benzoylhydrazones as antioxidant agents: Synthesis, in vitro evaluation and structure-activity relationship studies

Acetophenone and its analogues are naturally-occurring compounds found in many foods and plants. In this study, a series of acetophenone benzoylhydrazones 5a-o were designed and synthesized as new potential antioxidant agents. Designed molecules contain hydrazone and phenolic hydroxyl moieties which possibly contribute to antioxidant activity. The antioxidant properties of compounds 5a-o in terms of reducing ability and radical-scavenging activity were assessed by using FRAP and DPPH tests, respectively. While the unsubstituted compound 5a had the superior capacity in the FRAP assay, the 2,4-dihydroxyacetophenone analogue 5g was the most potent radical scavenger in the DPPH method. The antioxidant potential of representative compounds 5a and 5g was further confirmed by TEAC and ORAC assays. Cell viability assays revealed that while the promising compounds 5a and 5g had no significant toxicity against HepG2 and NIH3T3 cells, they potently protected HepG2 cells against H2O2-induced oxidative damage at low concentrations. Furthermore, spectroscopic studies with different biometals demonstrated that 5g was able to interact with Cu2+ to form a 1:1 complex.

Gastrodin Protects against Ethanol-Induced Liver Injury and Apoptosis in HepG2 Cells and Animal Models of Alcoholic Liver Disease.

This study aims to investigate the protective effects of gastrodin (GSTD), a natural compound isolated from the root of Gastrodia elata BL., on ethanol-induced liver injury and apoptosis in HepG2 cells and animal models. For in vitro studies, GSTD was used to pre-treat the cells for 4 h followed by 600 mM of ethanol co-administration for 24 h. Alcoholic liver disease (ALD) of Sprague-Dawley (SD) rats was induced by chronic ethanol-feeding plus a single dose (5 g/kg) of acute ethanol administration, GSTD at different doses were co-administered for 8 weeks. For acute liver injury experiment of ICR mice, GSTD (100 mg/kg/d) was pre-treated for 3 d followed by ethanol administration (5 g/kg) for 3 times. The results showed that GSTD protects HepG2 cells from ethanol-induced toxicity, injury, and apoptosis significantly. Co-administered with ethanol, GSTD prevented the loss of mitochondrial membrane potential, reduced the release cytochrome c from mitochondria, and inhibited the activation of caspase-3 in HepG2 cells. In SD rats induced by chronic ethanol-feeding, GSTD significantly restored liver function and ameliorated pathological changes of the liver. In rat liver, GSTD greatly suppressed the activation of caspase-3 and inhibited hepatocellular apoptosis. In ethanol-induced acute liver injury of ICR mice, GSTD reduced liver acetaldehyde and suppressed the up-regulation of alcohol dehydrogenase (ADH) and CYP2E1 significantly. Our results demonstrate that GSTD is efficacious in protecting liver cells from ethanol-induced injury and apoptosis; it may be useful for the development of novel agents for the treatment of ALD in the future.

TAT-mediated intracellular delivery of carboxypeptidase G2 protects against methotrexate-induced cell death in HepG2 cells

Side effects of methotrexate (MTX) especially hepatotoxicity limits clinical applications of this anticancer agent. Carboxypeptidase G2 (CPG2) is administrated for the treatment of elevated plasma concentrations of MTX. In this study, we have investigated the intracellular delivery of CPG2 fused to the transactivator transduction domain (TAT) and its protective effects against MTX-induced cell death of HepG2 cells. We have observed that both native and denatured forms of the enzyme transduced into the HepG2 cells efficiently in a concentration and time-dependent manner. The denatured protein transduced with higher efficiency than the native form and was functional inside the cells. MTX exposure significantly decreased HepG2 cell viability in a dose- and time-dependent manner. The cell viability after 24 and 48 h of incubation with 100 μM MTX was reduced to 44.37% and 17.69%, respectively. In cells pretreated with native and denatured TAT-CPG2 protein the cell viability was 98.63% and 86.31% after 24 and 48 h, respectively. Treatment with MTX increased the number of apoptotic HepG2 cells to 90.23% after 48 h. However, the apoptosis percentage in cells pretreated with native and denatured TAT-CPG2 was 21.49% and 22.28%, respectively. Our results showed that TAT-CPG2 significantly prevents MTX-induced oxidative stress by decreasing the formation of ROS and increasing the content of glutathione (GSH) and catalase activity. Our finding indicates that both native and denatured TAT-CPG2 strongly protect HepG2 cells against MTX-induced oxidative stress and apoptosis. Hence, intracellular delivery of CPG2 might provide a new therapeutic strategy for protecting against MTX mediated cytotoxicity.

Persimmon vinegar polyphenols protect against hydrogen peroxide-induced cellular oxidative stress via Nrf2 signalling pathway

Since polyphenols are known to exhibit antioxidative properties, we prepared and characterized persimmon vinegar polyphenols (PVP) in this study. Furthermore, we investigated the protective effect of PVP on hydrogen peroxide (H2O2)-induced oxidative stress in HepG2 cells and its underlying mechanisms. Our results showed that flavon-3-ols were the predominant polyphenols in PVP. Pre-treatment with PVP significantly decreased (p < 0.05) H2O2-induced cell damage in a dose-dependent manner, accompanied by decrease in lactate dehydrogenase (LDH) leakage, aminotransferase activities, and ROS accumulation. Moreover, PVP upregulated the expression of antioxidative enzymes, such as heme oxygenase-1 (HO-1) and NAD(P)H: quinone oxidoreductase 1 (NQO1), and increased the levels of glutathione. Western blotting results showed that PVP induced the nuclear translocation of nuclear factor (erythroid-derived-2)-related factor 2 (Nrf2). Taken together, our results indicated that PVP effectively protected HepG2 cells against oxidative stress via activation of the Nrf2 antioxidative pathway.

Quantification and cytoprotection by vanillin, 4-methylguaiacol and 4-ethylguaiacol against AAPH-induced abnormal oxidative stress in HepG2 cells.

Vanillin, 4-methylguaiacol, and 4-ethylguaiacol, three phenolic compounds in Gujinggong (GJG) Chinese baijiu (Chinese liquor), were quantified by liquid–liquid extraction (LLE) combined with gas chromatography-mass spectrometry (GC-MS) and evaluated for their possible cytoprotective effects by AAPH-induced HepG2 cell model. To confirm whether vanillin, 4-methylguaiacol, and 4-ethylguaiacol protected HepG2 cells against AAPH-induced abnormal oxidative stress via motivating the Keap1–Nrf2 pathway, the gene and protein expression of Nrf2, Keap1, SOD, CAT, and GPx from the Keap1–Nrf2 pathway were measured with real-time PCR and western blot. Three levels of treatment doses (1000, 500, and 100 mg L−1) were applied. Results showed that vanillin, 4-methylguaiacol, and 4-ethylguaiacol exhibited potent cytoprotective effect in a dose-dependent manner, greatly alleviating or reversing the increased oxidative stress induced by AAPH through up-regulating the mRNA and protein expression levels of Nrf2, SOD, CAT, and GPx, and thereby, significantly improving the intracellular antioxidant defense system in HepG2 cells (p < 0.05). Based on these findings, it was confirmed that vanillin, 4-methylguaiacol, and 4-ethylguaiacol, natural components of Chinese baijiu, were able to modulate the expression of Nrf2 and its downstream antioxidative enzymes (i.e., SOD, CAT, and GPx) against AAPH-induced abnormal oxidative stress. Further, this study lays the foundation for better illustrating the health benefits of Chinese baijiu.

Epimedium koreanum Ameliorates Oxidative Stress-Mediated Liver Injury by Activating Nuclear Factor Erythroid 2-Related Factor 2.

Oxidative stress induced by reactive oxygen species is the main cause of various liver diseases. This study investigated the hepatoprotective effect of Epimedium koreanum Nakai water extract (EKE) against arachidonic acid (AA)[Formula: see text][Formula: see text][Formula: see text]iron-mediated cytotoxicity in HepG2 cells and carbon tetrachloride (CCl4-)-mediated acute liver injury in mice. Pretreatment with EKE (30 and 100[Formula: see text][Formula: see text]g/mL) significantly inhibited AA[Formula: see text][Formula: see text][Formula: see text]iron-mediated cytotoxicity in HepG2 cells by preventing changes in the expression of cleaved caspase-3 and poly(ADP-ribose) polymerase. EKE attenuated hydrogen peroxide production, glutathione depletion, and mitochondrial membrane dysfunction. EKE also increased the nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2), transactivated anti-oxidant response element harboring luciferase activity, and induced the expression of anti-oxidant genes. Furthermore, the cytoprotective effect of EKE against AA[Formula: see text][Formula: see text][Formula: see text]iron was blocked in Nrf2 knockout cells. Ultra-performance liquid chromatography analysis showed that EKE contained icariin, icaritin, and quercetin; icaritin and quercetin were both found to protect HepG2 cells from AA[Formula: see text][Formula: see text][Formula: see text]iron via Nrf2 activation. In a CCl4-induced mouse model of liver injury, pretreatment with EKE (300[Formula: see text]mg/kg) for four consecutive days ameliorated CCl4-mediated increases in serum aspartate aminotransferase activity, histological activity index, hepatic parenchyma degeneration, and inflammatory cell infiltration. EKE also decreased the number of nitrotyrosine-, 4-hydroxynonenal-, cleaved caspase-3-, and cleaved poly(ADP-ribose) polymerase-positive cells in hepatic tissues. These results suggest EKE is a promising candidate for the prevention or treatment of oxidative stress-related liver diseases via Nrf2 activation.

Development, characterization, antioxidant and hepatoprotective properties of poly(Ɛ-caprolactone) nanoparticles loaded with a neuroprotective fraction of Hypericum perforatum

Quercetin and biapigenin are antioxidant and neuroprotective compounds present in Hypericum perforatum, with potential application in neurodegenerative diseases. Quercetin has shown to have excellent antioxidant activities. Biapigenin possesses a distinctive mechanism of action, preventing the onset of calcium deregulation and mitochondrial dysfunction. The main aim of this study was to establish a new delivery system encapsulating H. perforatum neuroprotective fraction, isolated from it,containing quercetin and biapigenin into poly(Ɛ-caprolactone) (PCL) nanoparticles. It also aimed to study its hepatoprotective potential. Different formulation parameters were optimized, resulting in a stable formulation of polymer:compounds ratio 1:0.1 with a mean particle size of 185nm, zeta potential around −20mV and association efficiency close to 100%. Compounds in vitro release, under physiological conditions, showed an initial burst followed by a sustained release. The antioxidant functional properties of these compounds were not altered by encapsulation. PCL-loaded nanoparticles protected HepG2 cells from intrinsic compound toxicity at high concentrations. Depending on the incubation regimen, quercetin-biapigenin PCL-loaded nanoparticles or free compounds were more effective in protecting HepG2 cells against tert-butylhydroperoxide-induced toxicity. This is the first report of the encapsulation of a quercetin-biapigenin mixture in a polymeric matrix, specifically, in PCL, with synergic anti-oxidant and hepatoprotective effects.

알코올성 지방간 유발 마우스에서 다슬기 유래 가수분해물의 간 보호 효과

Alcoholic steatosis is a fundamental metabolic disorder and may precede the onset of more severe forms of alcoholic liver disease. In this study, we isolated enzymatichydrolysate from Semisulcospira libertine by alcalase hydrolysis and investigated the protective effect of Semisulcospira libertine hydrolysate on liver injury induced by alcohol in the mouse model of chronic and binge ethanol feeding (NIAAA). In an in vitro study, the hydrolysate protects HepG2 cells from ethanol toxicity. Liver damage was assessed by histopathological examination, as well as by quantitating activities of serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP). After the administration of S. libertina hydrolysate, fat accumulation and infiltration of inflammatory cells in liver tissues were significantly decreased in the NIAAA mouse model. The elevated levels of serum AST, ALT, and ALP activities, along with the lipid contents of a damaged liver, were recovered in experimental mice administrated with S. libertina hydrolysate, suggesting its role in blood enzyme activation and lipid content restoration within damaged liver tissues. Moreover, treatment with S. libertine hydrolysate reduced the expression rate of cyclooxygenase (COX-2), interleukin (IL)-1β, and IL-6, which accelerate inflammation and induces tissue damage. All data showed that S. libertine hydrolysate has a preventive role against alcohol-induced liver damages by improving the activities of blood enzymes and modulating the expression of inflammation factor, suggesting S. libertine hydrolysate could be a commercially potential material for the restoration of hepatotoxicity.

Endoplasmic reticulum stress-mediated autophagy activation attenuates fumonisin B1 induced hepatotoxicity in vitro and in vivo

Although pathological characteristics of fumonisin B1 are known to induce hepatic injury over prolonged periods, the cellular defense mechanisms against the detrimental effects of FB1 are still unknown. The underlying mechanisms of FB1 toxicity are thought to be related with the inhibition of ceramide synthase, causing an accumulation of sphingoid bases, which in turn cause development of oxidative stress. Herein, we investigated whether autophagy, a cellular defense mechanism, protects liver cells from FB1 exposure. To accomplish this, we utilized HepG2 cells and a mouse model to study the effects of FB1 in the autophagy pathway. FB1 was capable of inducing autophagy via the generation of ROS, induction of endoplasmic reticulum stress, phosphorylation of JNK, suppression of mTOR and activation of LC3I/II in HepG2 cells and mice livers. Treatment of HepG2 cells with the ROS scavenger N-acetyl-l-cysteine alleviated ER stress stimulation and induced HepG2 cell death. Moreover, suppression of autophagy with 3-Methyladenine enhanced HepG2 cells apoptosis. Concurrently, four consecutive days exposure of mice livers to FB1 altered the levels of sphingoid bases, hepatic enzymes and induced histopathological changes. Moreover, the expression levels of major ER stress and autophagy-related markers such as PERK, IRE1-α, and LC3I/II also increased. Autophagy activation protected HepG2 cells and mice livers from the lethal effects of FB1. Hence, these findings specify that, the compounds that modify autophagy might be useful therapeutic agents for treatment of patients with FB1 induced liver ailments.